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“One or two in a thousand wake during surgery”

The nightmare – to wake up during surgery – is unfortunately a reality for one or two in a thousand of those anaesthetised. But it is possible to reduce the risk.

Everyone has heard or read horror stories about people who wake up during anaesthesia without the ability to communicate with their surroundings while the operation continues. This has meant that many worry about the risk of waking prior to surgery.

Rolf Sandin, adjunct Professor of Physiology, Anaesthesiology and Intensive Care at Karolinska Institutet and Head Physician at Kalmar County Hospital has dedicated 20 years of his research to this issue.

“There are four major studies into this in the world, where we have conducted one, and have all arrived at roughly the same conclusion; between one and two persons per thousand are affected.

The higher risk applies when muscular blocking agents are used as these make it more difficult to see when a patient begins to come to consciousness again. Additionally, there are a small number of patients who do not react as expected.

“When a patient wakes up during surgery, basically it is always about whether the patient has received sufficient anaesthetic. The reason for this could be that people may have a slightly different tolerance for anaesthetics, but also that some do not experience the rise in blood pressure and heart rate when waking that most people do.

Consequently they do not exhibit the classic signs that controls the anaesthesia,” says Rolf Sandin. Despite the terrible situation to wake up in the middle of one’s own operation it seems that not everyone experiences it as shocking.

“About one-third suffer from severe anxiety, and just as many experience severe pain while it is in progress,” says Rolf Sandin.

Approximately half suffer flashbacks and recurring nightmares, which for many subside after 1-2 months.

“Yet unfortunately a very small percentage of patients suffer full-blown post-traumatic stress that in the worst cases affects them for the rest of their lives,” he adds.

However, there are ways to reduce the risk of patients waking up during anaesthesia One way is to measure brain activity with electroencephalography, or EEG, during the operation. Rolf Sandin has published three studies that show EEG could reduce the risk by 80 per cent. However, the method is not entirely clear, and in addition, it does not work with all anaesthetics, which means it use is currently limited. Recently, new research has shown how additional information about the brain's communication pathways may make the method unambiguous, which gives us hope.